THERMAL DEATH-POINT OF LIVING MATTER. 189 



Brewer in California ; and 208 as observed by Descloizeaux in Ice- 

 land." As we have no grounds for criticising these observations, we 

 are bound to look upon them, provisionally at least, as correct and 

 taken with all due care, though it is only fair to add that both Max 

 Schultze and Cohn appear to be not altogether satisfied with some 

 statements of the same kind. 1 Such instances, if thoroughly accurate, 

 may perhaps be taken as examples of the highest temperature which it 

 is possible for living matter to endure, even where it has been inured 

 to its influence in the most gradual manner. And the real point of 

 view from which these facts should be regarded is, indeed, pointed out 

 by Prof. Wymau when he says : " Having become adapted through a 

 long series of years to their surroundings, such organisms may be sup- 

 posed to live under circumstances the most favorable possible for sus- 

 taining life at a high temperature. It is a well-known physiological 

 fact that living beings may be slowly transferred to new and widely 

 different conditions without injury ; but if the same change is suddenly 

 made, they perish. In the experiments made in our laboratories, the 

 change of conditions is relatively violent, and therefore liable to de- 

 stroy life by its suddenness." 



3. If we omit, therefore, the facts concerning the existence of 

 living organisms in thermal springs which are altogether peculiar, and 

 which lie outside the boundaries of our present inquiry, all that we 

 know about the unaccustomed influence of high temperatures upon 

 living things can easily be shown to be even more harmonious than it 

 may at first glance appear. We have only to bear in mind two or 

 three general principles in order to be able to harmonize the several 

 experimental results arrived at with the now very generally admitted 

 doctrine as to the oneness or generic resemblance existing between all 

 forms of living matter. We must bear in mind, first of all, the con- 

 sideration enforced by Spallanzani, that there are different grades of 

 vitality, or, in other words, forms of living matter which exhibit more 

 or less of the phenomena known as vital, and that of these forms those 

 which exhibit the most active life are those which would be most 

 easily killed by heat. Thus we should expect the latent "life" of the 

 germ, egg, or seed, to be less easily extinguished than the more subtile, 

 and, at the same time, more active life of the fully-developed tissue- 

 element or organism ; and we should also expect that the vegetal ele- 

 ment or organism would, as a rule, be less readily killed than the more 

 highly-vitalized animal element or organism. These principles, based 

 upon the consideration of relative complexity of life, are, however, 

 subject to the influence of a disturbing cause, since we must also take 

 into account, in the case of animals, whether we have to do with the 

 elements of a warm-blooded or a cold-blooded organism, owing to the 

 fact that custom or habitual conditions tend to render the more active 

 tissue-elements of warm-blooded animals better able to withstand the 

 1 Max Schultze, " Das Protoplasma," Leipsic, 1863, p. 67. 



